Honey has been used for centuries to treat skin conditions and is known historically for its effectiveness in the treatment of wounds and burns.
In recent times, manuka honey, in particular, has received attention for its reported antibacterial activity. This honey is produced by bees who harvest the nectar of Leptospermum scoparium. The antibacterial activity of manuka honey has been labelled the “Unique Manuka Factor” (UMF) and it has been reported that the UMF derives from the presence of methylglyoxal in the honey.
WO 2007/137369 describes medicinal compositions containing honey derived from Leptospermum scoparium and their use in treating ophthalmic, respiratory or otic conditions caused by microbial infections.
Kanuka honey, on the other hand, is a bio-active honey that is less well-known than manuka honey. It is produced by bees who harvest the nectar of the kanuka (Kunzea ericoides) and has been found to have anti-microbial activity against Staphylococcus aureus. Furthermore, raw kanuka honey has been reported to have methylglyoxal levels of about 1024 mg/kg and medical grade kanuka honey has been reported to have methylglyoxal levels of 1154 mg/kg (S Holt et al., The Journal of Complementary and Alternative Medicine, (2012) 18(3), 203-204).
There are difficulties associated with the use of honey as a skin treatment. Honey itself is sticky and strong smelling. The consistency of honey varies with temperature. For example, at room temperature honey might be a of suitable consistency for application to the skin, but at lower temperatures, such as a normal household refrigeration temperature of about 4° C., honey can become hard and can crystallise, which reduces its ease of use and appeal to users. In warmer conditions, its viscosity decreases and honey can become too “runny” for application to skin.
Some efforts have been made in formulating honeys, e.g. for wound treatment. NZ 542258 describes a manuka honey composition for treating wounds. The composition includes a viscosity increasing agent which increases, or at least maintains, the viscosity of the composition after application to a wound. NZ501687 describes a wound dressing composition that includes honey and one or more gelling agents, such as alginate-based materials.
However, while formulating honey with other additives might address some of the difficulties associated with using honey as a skin treatment, dilution of the honey can result in the loss of its particular biological activity (e.g. see S Holt et al., The Journal of Complementary and Alternative Medicine, (2012) 18(3), 203-204).
There is therefore a need for honey compositions that are stable at a variety of temperatures, and wherein the honey retains its biological activity.
It is an object of the invention to provide a composition comprising honey and glycerine, and methods for preparing such compositions, that overcome some of these problems, or to at least provide a useful alternative.